According to the Institute for Local Self-Reliance, one of every two households in the United States has a Prime Membership, and 43 percent of all online sales went through Amazon last year.

So, is Amazon getting too big?

“From the standpoint of U.S. antitrust law, probably no,” said Tom Cotter, a professor of antitrust law at the University of Minnesota. “It’s not really an offense simply to be a big company. It’s not really an offense simply to be a monopoly.”

Cotter says antitrust law in the U.S. focuses on the consumer, rather than competitors. For an antitrust violation to occur, government regulators would have to prove a company had a monopoly and was engaging in practices that harm consumers.